High-yield Bioethanol Production from Cashew Apple in Atakpamé

The current work aimed to determine the efficiency of bioethanol production from cashew apples. To optimize bioethanol production yield, the juice extracted by mechanical pressing of cashew apples was concentrated into normal gravity (NG) must (20°Brix) and very high gravity (VHG) must (28°Brix). A parallel experiment was conducted using sucrose as a fermentable model substrate. Urea was added to enhance the fermentation capacity of the yeast. Batch and fed-batch fermentation processes were monitored by refractometric method, and the alcoholic content of the musts was determined using pycnometric method. The results showed that the ethanol produced rates (% vol.) with urea (2 g/L) in VHG must by the fed-batch process, and in VHG and NG musts by the batch process, were as follows: 16.36, 15.44, and 9.62, respectively. In comparison, ethanol obtained rates without urea were 15.37, 14.37, and 10.34 under the same conditions. Juice concentration, urea addition, and fed-batch fermentation process were used to optimize bioethanol production yields from cashew apples. In fact, the technology of bioethanol production adopted in the current study would generate additional benefits for farmers.